Background

Burwood Resource Recovery Park Limited (BRRP) was established urgently to manage the receipt and resource recovery processing of mixed demolition material from Christchurch’s earthquakes.

The operation was initially developed by Christchurch recycling service provider Waste Management (NZ) Ltd (Waste Management), working in partnership with Christchurch City Council (CCC) and Canterbury Earthquake Recovery Authority (CERA).

The BRRP company is now under the ownership of Transwaste Canterbury Limited (Transwaste). Transwaste is a joint venture between Waste Management and five Canterbury Councils (Christchurch, Ashburton, Selwyn, Waimakariri and Hurunui), and owns Kate Valley Landfill which takes all municipal solid waste from the five Council areas. The operation is establishing a state-of-the-art resource recovery plant at Burwood.

Transwaste is determined to deliver the best possible outcomes from the Christchurch demolition and rebuilding programmes, by

  • maximising the recovery and re-use of valuable and necessary building materials
  • reducing the volume of residual demolition waste to landfill
  • minimising costs.

The BRRP operation is aiming to recycle 50% of the debris material it will receive from the city’s quake damaged commercial and residential buildings. This target has been revised from 75%, based on the lower quality of material being received as a result of on-site material recovery by demolition contractors and free disposal of potentially recyclable rubble at Lyttelton Port.

It is essential to minimise waste going to the landfill at Kate Valley. This landfill has a limited daily volume it can handle, most of which is taken up with normal municipal solid waste. Sending all the unprocessed demolition material to Kate Valley could take 20 years – clearly not an option.

The Size of the Task

CERA estimates the building demolition material to be removed from Christchurch at 4.25 million tonnes.

This will come from the city facing the demolition of

  • as many as 1000 CBD buildings
  • up to 500 commercial buildings outside the CBD
  • potentially over 10,000 houses.

This volume is the equivalent of around 20 years of normal municipal solid waste to the Canterbury regional landfill at Kate Valley.

Around perhaps one quarter of this demolition material is expected to be taken to Burwood for recycling. This will be the largest recycling undertaking of its type in Australasia.

The mixed demolition material will require major processing so it can be separated into useful components. After high initial volumes immediately after the February 2011 earthquake, it is now arriving at Burwood at up to a rate of around 300 tonnes a day, and is likely to continue arriving until late 2017.

The intensive resource recovery phase of that material is likely to take five years.

BRRP is investing many millions of dollars in plant and equipment suited to the mixed debris material being received at Burwood. This includes the most sophisticated material sorting process ever seen in Australasia.

The Process

BRRP faces a major challenge at the Burwood site to manage the receipt of the material in a safe and efficient manner. The Burwood site has been receiving mixed building demolition material since 7th March 2011.

Every truckload arriving at Burwood is visually inspected so its contents can be assessed and confirmed as acceptable for the site. The truck driver is directed to the correct location within the stockpile zone, depending on the type of load. This occurs 12 hours a day, six days per week.

Stockpiling the material needs to be performed carefully, to preserve the recovery potential of the materials. The stockpile may grow as high as 20 metres.

A sophisticated recycling plant will be constructed to undertake the fine sorting of material, through a combination mechanised and manual state of the-art processing plant. Magnets are used to recover ferrous metals and eddy current drums used to separate non-ferrous metals. Sorting line staff will remove fibre (cardboard, paper), fittings, untreated timber, plastics, gib/plaster board, and other reusable materials.

Residual waste from the fine sorting process will go to a specially constructed new high standard landfill, situated to the north-east side of the old closed Burwood landfill.

The BRRP recycling plant may have to operate 16 hours a day, six days a week for five years to work through the expected volume of material.

Recovery and recycling operations are expected to begin in the latter half of 2012, after the systems and power supply are established and staff appointed and trained (about 30 likely to be needed.)